1. Field of the Invention
The present invention relates to a substrate processing apparatus and a substrate processing method which supply a processing liquid to a substrate to perform a predetermined wet processing to the substrate, the substrate including semiconductor wafers, glass substrates for photomask, glass substrates for liquid crystal display, glass substrates for plasma display, substrates for FED (field emission display), substrates for optical disks, substrates for magnetic disks, substrates for magnet-optical disks, etc.
2. Description of the Related Art
In a production process of electronic components such as semiconductor devices and liquid crystal display devices, a predetermined wet processing is performed to the substrates by sequentially supplying plural kinds of processing liquid such as chemical solution and rinsing solution to the substrates. In a substrate processing apparatus of a single wafer processing type which processes a substrate one by one, plural kinds of processing liquid are sequentially supplied to the substrate while the substrate is rotated in a horizontal posture to perform a wet processing to the substrate with respect to each processing liquid. In order to enable reuse of the chemical solution as well as preventing dispersion of the processing liquid shaken off from the substrate, the processing liquids which are shaken off from the substrate are separately retrieved with respect to each kind of processing liquid (see JP-A-5-190442). In the apparatus described in JP-A-5-190442, a first and a second cups are provided so as to surround a spin chuck which holds and rotates the substrate in a horizontal posture. And a first chemical solution shaken off from the rotating substrate is received by the first cup for retrieval, whereas a second chemical solution shaken off from the rotating substrate is received by the second cup for retrieval. Specifically, it is possible to retrieve mutually different chemical solutions (the first and the second chemical solutions) separately by means of the first and the second cups.
In a substrate processing apparatus of a batch processing type which processes plural substrates collectively, the wet processing is performed to the plural substrates by immersing the plural substrates in a processing liquid stored in a processing tank. There is a case that the wet processing is performed to a substrate with respect to each processing solution by sequentially replacing a processing liquid stored in the processing tank with mutually different plural kinds of processing liquid (see JP-A-2000-286224). In the apparatus described in JP-A-2000-286224, it is arranged that the processing liquids discharged from the processing tank are separately retrieved with respect to each kind of processing liquid. Specifically, the processing liquid overflowed from the processing tank is guided to respective destinations according to kinds of the processing liquid via branch pipes branched from a single pipe to a number of kinds of the processing liquid. Each branch pipe is equipped with an on-off valve. The destination of the processing liquid overflowed from the processing tank is switched by controlling opening and closing of the respective on-off valves. Consequently, the processing liquids are sent to the respective destinations according to the kinds of the processing liquid to separately retrieve the processing liquid. That is, when a first chemical solution is discharged from the processing tank, only the on-off valve mounted on the branch pipe for the first chemical solution is opened while the on-off valves mounted on the other branch pipes are closed to retrieve the first chemical solution. Further, when a second chemical solution is discharged from the processing tank, only the on-off valve mounted on the branch pipe for the second chemical solution is opened while the on-off valves mounted on the other branch pipes are closed to retrieve the second chemical solution.